1. Field of the Invention
The present invention relates to key-operated steering shaft locking devices for motor vehicles. More particularly, the invention relates to such a device comprising a key-operated rotatable cylinder and a latch, the latch being operable to move perpendicularly to the axis of rotation of the cylinder to lock the steering shaft against rotation.
2. Description of the Prior Art
Most known key-operated steering shaft locking devices are provided with a locking bolt, or latch, which is operable to lock the shaft by moving parallel to the longitudinal axis of a rotatable lock cylinder operatively associated therewith and activated by the key. The longitudinal movement of the latch can cause such devices to be difficult to assemble, and can result in increased wear of moving parts and diminished reliability in service. Indeed, within the housings of typical locking devices the movable locking and unlocking mechanisms are usually placed in a side-by-side configuration, parallel to relatively complex mechanisms which enable, for example, insertion of the ignition key into the cylinder, rotation of the cylinder with the key therein, and withdrawal of the key in certain positions of rotation of the cylinder and not in others. Since the practical reasons the dimensions of the assembled device are limited by the size of its housing, manufacturers often are forced to use very precise dimensional tolerances for component parts, thus increasing the risk of relatively fast wear and diminished reliability.
Furthermore, in steering shaft locking devices of the type described in the preceding paragraph, the number of parts necessary for proper operation is comparatively high, and, since all of these parts must be integrated into a limited space, assembly difficulties can be significant. The assembly of such devices is, accordingly, often a slow operation, human errors being commonplace. An example of such a prior art steering locking device is disclosed in French Pat. No. 2,330,569.